Abstract
1. The morphological and physiological differences of tobacco seedlings grown in the bed of conditioned temperature, were observed, and then the successive developmental changes were sought when the seedlings were transplanted under various thermal conditions. In field. 2. The vegetative growth of seedling grown under low temperature (10∼20'C) was inferior to that of high temperature (20∼30'C), but it was observed that the former is specialized with the morphological and physiological character to resist against such an unfavorable condition as transplanting or low temperature. The differences of seeding characters were shown obviously under low temperature condition, and especially the development of seedling nursed in low temperature bed was accelerated when grown under low temperature in field. 4. The fact that the different characters of seedling as to flower ignition could be identified only in the case of low temperature condition, is considered to be due to the different rooting ability as well as the thermal response accumulated during the seedling period.
